Cumulative incidence of patients with disc hemorrhages in glaucoma and the effect of therapy.

Abstract

In this longitudinal study, the cumulative incidence of patients with glaucoma and disc hemorrhages was investigated. A possible effect of glaucoma therapy on the incidence rate of disc hemorrhages was evaluated. A group consisting of 68 patients with primary open-angle glaucoma (POAG), 34 with normal-pressure glaucoma, and 125 with suspected glaucoma (mean follow-up, 7.3 +/- 2.5 years; range 3-13 years) was observed closely with quarterly examinations. In normal-pressure glaucoma, the cumulative incidence of patients with disc hemorrhages was 35.3%, which was significantly higher than for those with POAG (10.3%; P < 0.01) and for those with suspected glaucoma (10.4%; P < 0.001). The mean follow-up period before a first disc hemorrhage was detected was 2.5 +/- 2.8 years. In the bleeders, recurrent disc hemorrhages were observed in 67% of the patients with normal-pressure glaucoma, 29% of those with POAG, and 54% of glaucoma suspects. In normal-pressure glaucoma, therapy had no effect on the incidence rate of disc hemorrhages. In glaucoma suspects, a significant reduction of the incidence rate of disc hemorrhages per year (0.11 +/- 0.04) was observed during episodes with therapy compared with episodes without (0.43 +/- 0.15; P < 0.05). A concept of two populations (i.e., one with disc hemorrhages and the other never having them) seems to be valid for normal-pressure glaucoma, but not for POAG and suspected glaucoma. The cumulative incidence of initial disc hemorrhages increases with time in POAG and suspected glaucoma, but reaches a limit in normal-pressure glaucoma. Glaucoma therapy may reduce the incidence rate of all, initial and recurrent, disc hemorrhages in patients with high pressures, but not in patients with normal-pressure glaucoma.